Thanks & will do! For Jr's T-S set-up, I plan M11 springs (compact diameter) on guide rods near the outsides of the BC in the rear. Short guide tubes in the buttplate will keep the springs guided thru the stroke. The guide rods will ALMOST extend to the guide tubes creating a simple telescopic effect. The BC ext may need side-reinforcements if the diagonal "L" needs narrowed (for the springs/guides to clear). It may sound a little mickey mouse, but I believe it will work. Let's call it the 'no-mill' approach

Just snapped this after writing the above explanation. A pic is worth a thousand words. Still need to find correct-size tubing for the guides and build a butt-plate. You can see I cobbled together the top part for the TC latch, because I didn't have 1 1/8" tubing. It doesn't set on the top rails like it should. With the RPD TC, I should've removed the latch from the TC to fit that part, but didn't. The latch screw is STAKED

I'm open to suggestions for common small dia springs. The smaller the spring dia, the less the "L" ext will need narrowed/weakened. I don't want it to break after 10 shots. M11 springs are .275"OD x 11" OAL and compress to 5". There is 4" for 'stacked compression space', from the butt of the BC to the back end of the ext

This is the BACK of the stroke. Jr has 5 1/8" BC stroke whereas my MG47 only has 4 1/8", though it's rcvr is 1.5" longer. That's because of the HOLLOW stock mount, allowing the BC ext to recess into it. Building Jr more compact, yet having a longer stroke was a learning curve. Who knows how far this design will progress a year from now -

The 7.62x25 will be a completely new build. A BC for it is on the way from Shadow Walker (THANKS) and I have all the other parts. I'm excited because of how easily they click in & out of the links, which should allow a weaker spring, leaving most of it's lesser power to cycle the TC/ feed mech (instead of overcoming a strong recoil spring). THEY ARE TOO LOOSE in the "L" link belts. This build won't happen anytime real soon. Knob Creek & Cheyenne Wells in CO are coming up, so not much time to build. If anyone else is persuing one I'd be glad to share what I've come up with, to help jump-start yours. A seperate thread for the 7.62x25 will be in order. EIGHT CENTS A RD makes it a gotta-do

I've shot the MG47 & Jr every day I've been home. Fortunate to have a place nearby to shoot (5 minutes away) but it's being excavated for development, so that won't last much longer.

HERE is where we go out to shoot when we really shoot. It's a secluded bowl-shaped valley about 1 x 2 miles. No people nor houses for miles. If I'd win the lottery, I'd buy it all and retire there. But I don't play the lottery
That's me, Marty, and famed 1919/MG34/MG42 CII builder John McGuire, at "Thunder Valley". Thought you guys would enjoy that one

Steve
I see you got your BC annealed, drilled and tapped. Was it as hard as the ones I encountered? Got the MG47ES to feed, the op. handle on and the grip on. Also, I threaded a Bulgarian bulged trunion for a heavy 28" Ruger No 1 308 barrel, head spaced and the barrel turned for a RPK gas block for Ian's M-76 he is working on. Hope to be able to test fire the ES this week end.
McMaster Carr has a good selection of springs. Delivery about 3 day from Kalifornia.
SS.

The HARD part hasn't been done yet - that was just a mock-up of what's planned. plus the buttplate w/ tubes - I'm guessing a day's work. Ian's project sounds like it'll be a hard-hitting tack-driver - I can't wait to see your MG47ES!